文献类型：期刊文献

英文题名：Band Engineering in Core/Shell ZnTe/CdSe for Photovoltage and Efficiency Enhancement in Exciplex Quantum Dot Sensitized Solar Cells

作者：Jiao, Shuang[1];Shen, Qing[2,3];Mora-Sero, Ivan[4];Wang, Jin[1];Pan, Zhenxiao[1];Zhao, Ke[1];Kuga, Yuki[2];Zhong, Xinhua[1];Bisquert, Juan[4,5]

机构：[1]E China Univ Sci & Technol, Inst Appl Chem, Key Lab Adv Mat, Shanghai 200237, Peoples R China;[2]Univ Electrocommun, Dept Engn Sci, Chofu, Tokyo 1828585, Japan;[3]Japan Sci & Technol Agcy JST, CREST, Kawaguchi, Saitama 3320012, Japan;[4]Univ Jaume 1, Dept Fis, Photovolta & Optoelect Devices Grp, Castellon de La Plana 12071, Spain;[5]King Abdulaziz Univ, Dept Chem, Fac Sci, Jeddah 21589, Saudi Arabia

年份：2015

卷号：9

期号：1

起止页码：908

外文期刊名：ACS NANO

收录：;EI(收录号：20150500476953);WOS:【SCI-EXPANDED(收录号:WOS:000348619000100)】；

基金：We acknowledge the National Natural Science Foundation of China (Nos. 21421004, 91433106, and 21175043), the Science and Technology Commission of Shanghai Municipality (11JC1403100 and 12NM0504101), the Fundamental Research Funds for the Central Universities in China, the CREST program of Japan Science and Technology Agency (JST), and Grant in Aid for Scientific Research (No. 26286013) from the Ministry of Education, Sports, Science and Technology of the Japanese Government for financial support.

语种：英文

外文关键词：quantum dot sensitized solar cells; high photovoltage and efficiency; band gap engineering; type-II core/shell structure; ZnTe/CdSe quantum dots

摘要：Even though previously reported CdTe/CdSe type-II core/shell QD sensitizers possess intrinsic superior optoelectronic properties (such as wide absorption range, fast charge separation, and slow charge recombination) in serving as light absorbers, the efficiency of the resultant solar cell is still limited by the relatively low photovoltage. To further enhance photovoltage and cell efficiency accordingly, ZnTe/CdSe type-II core/shell QDs with much larger conduction band (CB) offset in comparison with that of CdTe/CdSe (1.22 eV vs 0.27 eV) are adopted as sensitizers in the construction of quantum dot sensitized solar cells (QDSCs). The augment of band offset produces an increase of the charge accumulation across the QD/TiO2 interface under illumination and induces stronger dipole effects, therefore bringing forward an upward shift of the TiO2 CB edge after sensitization and resulting in enhancement of the photovoltage of the resultant cell devices. The variation of relative chemical capacitance, C mu, between ZnTe/CdSe and reference CdTe/CdSe cells extracted from impedance spectroscopy (IS) characterization under dark and illumination conditions clearly demonstrates that, under light irradiation conditions, the sensitization of ZnTe/CdSe QDs upshifts the CB edge of TiO2 by the level of similar to 50 mV related to that in the reference cell and results in the enhancement of Voc of the corresponding cell devices. In addition, charge extraction measurements have also confirmed the photovoltage enhancement in the ZnTe/CdSe cell related to reference CdTe/CdSe cell. Furthermore, transient grating (TG) measurements have revealed a faster electron injection rate for the ZnTe/CdSe-based QDSCs in comparison with the CdSe cells. The resultant ZnTe/CdSe QD-based QDSCs exhibit a champion power conversion efficiency of 7.17% and a certified efficiency of 6.82% under AM 1.5G full one sun illumination, which is, as far as we know, one of the highest efficiencies for liquid-junction QDSCs.